1. Technical Field
The present invention relates to a relay device for accomplishing an electrical connection between relatively rotating members through the intermediary of a flexible flat cable. More particularly, it relates to a relay device equipped with a cutter which is arranged between a rotating member and an immovable member in a handle or the like and which cuts a flat cable as soon as the handle does not operate to rotate.
2. Description of the Related Art
This kind of relay device is disclosed in Japanese Unexamined Utility Model publication (kokai) No. 1-161589. In the publication, the relay device includes a first rotor having an inner cylinder, a second rotor having an outer cylinder surrounding the inner cylinder of the first rotor through an annular space, a flexible flat cable accommodated in the annular space defined between the inner cylinder and the outer cylinder in a spirally wound manner, and a cutter unit for cutting the flexible flat cable. Note, the flexible flat cable will be also referred as "the cable", hereinafter. The cutter unit is so constructed as to cut off the cable in either case that the cable is wound to the side of the inner cylinder over a first predetermined volume (permissible length) by relative rotations of the first and second rotors or that the cable is wound back to the side of the outer cylinder over a second predetermined volume.
In the above-mentioned relay device, however, there have been employed two kinds of cutter units: one is provided for cutting the cable in case that the cable is wound about the inner cylinder over the first predetermined volume; the other is provided for cutting the cable in case that the cable is wound back about the outer cylinder over the second predetermined volume. That is, the conventional relay device has been provided with two different cutter units in order to cut off the single cable. Consequently, the provision of the two cutter units in the relay device causes its manufacturing cost to be increased undesirably.